Question

嘿，我正在尝试创建Android应用程序，我可以在画布上绘制，底部有两个按钮我设法让绘图工作但是现在我需要添加两个按钮（一个用于将绘图画布保存到数据库（如果可能的话是Sqlite）或位图，另一个用于从sqlite导入图像并将其显示到graphicview）

现在我不知道我需要在其中添加哪些代码才能使保存和显示按钮正常工作，所以请帮我解释一下代码并感谢您的时间：）

这是我目前的代码（图形绘图工作正常，现在我需要保存和显示按钮的代码以及我在imageview.java和MainActivity.java中错过的内容）

GraphicsView.java

package org.example.graphics;

import java.util.ArrayList;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.RectF;
import android.graphics.Path.Direction;
import android.view.*;

public class GraphicsView extends View implements View.OnTouchListener {

public GraphicsView(Context context) {
    super(context);
    setBackgroundColor(Color.WHITE);
    setOnTouchListener(this);
}

ArrayList<MyPoint> arrOfPoints=new ArrayList<MyPoint>();

class MyPoint
{
    float x, y;
}
float downx, downy;

@Override
protected void onDraw(Canvas canvas) {
    // Drawing commands go here

    Paint rectPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
    rectPaint.setStyle(Paint.Style.FILL_AND_STROKE);
    rectPaint.setColor(Color.BLACK);
    canvas.drawRoundRect(new RectF(0, 0, 100, 100), 10, 10, rectPaint);

    rectPaint.setColor(Color.BLUE);
    rectPaint.setAlpha(40);
    canvas.drawCircle(300, 300, 200, rectPaint);
    canvas.drawRect(new RectF(40, 40, 200, 200), rectPaint);
    Paint textPaint = new Paint(Paint.ANTI_ALIAS_FLAG
            | Paint.STRIKE_THRU_TEXT_FLAG);
    canvas.drawText("Hello there!", 200, 200, textPaint);

    canvas.drawText("You clicked on " + downx + "," + downy, 200, 600,
            textPaint);
        for(int i=0;i<arrOfPoints.size();i++)
                {
                    canvas.drawCircle(arrOfPoints.get(i).x, arrOfPoints.get(i).y, 20, rectPaint);
                }

}

@Override
public boolean onTouch(View arg0, MotionEvent arg1) {
    int action = arg1.getAction();
    MyPoint p=null;
    switch (action) {
    case MotionEvent.ACTION_DOWN:
        downx = arg1.getX();
        downy = arg1.getY();

        p=new MyPoint();
        p.x=arg1.getX();p.y=arg1.getY();

        arrOfPoints.add(p);
        invalidate();
        break;
    case MotionEvent.ACTION_MOVE:
        downx = arg1.getX();
        downy = arg1.getY();
        p=new MyPoint();
        p.x=arg1.getX();p.y=arg1.getY();
        arrOfPoints.add(p);
        invalidate();
        break;
    case MotionEvent.ACTION_UP:

        break;
    case MotionEvent.ACTION_CANCEL:
        break;
    default:
        break;
    }
    return true;
}

MainActivity.java

package org.example.graphics;
import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.Path.Direction;
import android.graphics.RectF;
import android.os.Bundle;
import android.view.View;

public class MainActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(new GraphicsView(this));
}

main.xml中

 <?xml version="1.0" encoding="utf-8"?>
 <LinearLayout
 xmlns:android="http://schemas.android.com/apk/res/android"
 android:orientation="vertical"
 android:layout_width="fill_parent"
 android:layout_height="fill_parent"
 android:background="@drawable/background">

 <org.example.graphics.GraphicsView
   android:id="@+id/graphics"
   android:layout_width="fill_parent"
   android:layout_height="341dp" />

   <Button
    android:id="@+id/ChoosePictureButton"/>
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="Choose Picture"

 <Button
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="Save Picture" android:id="@+id/SavePictureButton"/>

</LinearLayout>

我的AndroidManifest.xml仍处于默认状态，因为我还没有编辑其中的任何内容

Answer 1

您可以在保存按钮单击侦听器中使用此代码。

int canvasWidth = 500;
int canvasHeight = 500;
View v = new GraphicsView(MainActivity.this);
Bitmap bitmap = Bitmap.createBitmap(canvasWidth, canvasHeight, Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
v.draw(canvas);

//now bitmap has your canvas image

//set it to your ImageView
yourImageView.setImageBitmap(bitmap);

//or save to sdcard
File dir = new File("/sdcard/yourAppFolder/");
if (!dir.isDirectory()) {
    dir.mkdirs();
}
File outputFile = new File(dir, "image.jpg");
OutputStream fout = null;
fout = new FileOutputStream(outputFile);
bitmap.compress(Bitmap.CompressFormat.JPEG, 100, fout);
fout.flush();
fout.close();

如何保存画布绘图并在单击按钮时显示它

1 个答案: